It is a known fact in the golf industry that the demand for high quality golf course bunkers has increased and all levels of golfers demand the same excellent bunker characteristic as found on championship golf courses. Golf courses spend an enormous amount of money and resources trying to keep sand bunkers in excellent playable conditions.
Green keepers and maintenance crews frequently spend considerable time and resources in maintaining sand bunkers and attempting to preserve the configuration and aesthetics of the bunkers, often at enormous costs. It is a matter of common experience that heavy rain erodes the sand in the bunker. The engineering phenomenon known as a radial slide is mainly the cause. A radial slide occurs in a sand bunker when the layer of sand becomes totally saturated (loaded) with water and washes down the slope of a bunker. When the eroded bunker sand washes, the native clay, silt, fine sand, and gravel that the floor of the bunker is compromised of, washes also.
This contaminates the bunker sand. The contaminated sand then becomes a mixture of the bunker sand and clays and does not drain as well as new sand due to the sands' pore spaces being filled with the finer clay. Green keepers and maintenance crews replace the contaminated sand back upon the slopes each time that a heavy rain occurs. With every rainfall, the sand becomes more contaminated. thus requiring repairs that are more frequent. After numerous washouts, the bunker sand no longer is clean and functional. Golfers complain about inconsistency and the only solution is to renovate the bunker.
One problem associated with golf course bunkers is the contamination of the sand, primarily, due to mud, clay, dirt, and gravels being mixed into the sand. This can occur from sand moving on the steep slopes from heavy rain events. The sand is contaminated from subgrade materials washing with the sand in these heavy rains, forcing green keepers to push or shovel the eroded and contaminated sand back up the slopes. This contaminated sand is then unknowingly mixed from the normal maintenance practice of using a mechanical rake after the erosion from heavy rainstorms.
After many cycles, the result is unsightly discolored sand with poor drainage. Every heavy rain events compound the problem further. In addition, this can change the consistency and playability of the sand for golfers.
Another problem associated with golf course bunkers is that due to the demand of special very white, angular, and well-drained sands by many golf courses, and the limited number of suppliers, these sands must be shipped from distances that can cause exorbitant shipping cost making the final sand cost to be very expensive.
Another problems associated with golf course bunkers is that some golf course designers insist on designing slopes of bunkers to be very steep so that the white sand can be seen from fairways or teeing ground. This is known as flashing the sand. It is known that sand cannot stay on steep slopes without constant replacement by green keepers. No method has considered what the maximum slope a particular sand should be placed.
A problem associated with golf course bunkers when using geotextile fabric liners on the floors and around the edges of bunkers to prevent erosion is that during rainstorms, the sand erodes down the slope of the bunker, thinning the layer of sand on the geotextile fabric or exposing the geotextile fabric. During routine maintenance, the geotextile fabrics are then torn and often ripped out by mechanical raking of the bunkers, causing the soil and gravel to contaminate the sand. Many golf courses have resorted to expensive hand labor to rake sand bunker that have geotextile fabric placed in them.
Another problem associated with golf course bunkers is the use of thicker matted geotextile fabric designed to allow water to move through the matt as a conduit thus preventing erosion and contamination. These matted geotextile fabric also tear by mechanical raking when sand gets thin as discussed above, but they also become flat in a short period of time and lose their ability to act as a conduit, thus they stop draining water quickly horizontally under the sand, increasing the potential for erosion of the sand to occur in heavy rainfall events. Although gravel placed beneath geotextile fabric has been used before to improve the speed of drainage, no method that locks the gravel, particles together forming a somewhat permanent and substantially porous solid mass liner has been used.
Another problem associated with golf course bunkers is erosion of native soil around the edges of the bunker from normal maintenance practices of edging or making a vertical cut in the sod of grass to make a clean edge. Greenkeepers often edge bunkers leaving exposed soil that erodes and contaminates the bunkers. Multiple techniques are currently employed in the prior art to design, construct, renovate, drain and maintain golf course sand bunkers and their edges.
Almost all techniques include the use of some type of drainage systems for the purpose of allowing water to exit from the bunker. In other techniques, liners have been used to reduce contamination of the sand and reduce erosion. However, various types of materials have been used with limited success.